BroadcastReceiver 之強制下線

登錄主界面

package com.gao.broadcastreceivertest;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

/**
 * 登錄界面
 */
public class LoginActivity extends BaseActivity {

    private EditText userName, password;
    Button login;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        userName = (EditText) findViewById(R.id.et_userName);
        password = (EditText) findViewById(R.id.et_password);

        login = (Button) findViewById(R.id.btn_login);

        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String account = userName.getText().toString().trim();
                String pwd = password.getText().toString().trim();

                if (account.equals("admin")&&pwd.equals("123456")){
                    Intent intent = new Intent(LoginActivity.this,MainActivity.class);
                    startActivity(intent);
                    finish();
                }else {
                    Toast.makeText(LoginActivity.this, "賬號或密碼輸入有誤", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

強制下線按鈕 界面

package com.gao.broadcastreceivertest;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

/*
廣播的最佳實踐——實現強制下線功能
 */
public class MainActivity extends AppCompatActivity {
Button offLine;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        offLine = (Button) findViewById(R.id.force_offline);

        offLine.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent("com.gao.broadcastreceiver.OFF_LINE");

                sendBroadcast(intent); //發送強制下線 廣播
            }
        });
    }
}

強制下線 廣播接收者

package com.gao.broadcastreceivertest;

import android.app.AlertDialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.view.WindowManager;

public class ForceOfflineReceiver extends BroadcastReceiver {
    public ForceOfflineReceiver() {
    }

    @Override
    public void onReceive(final Context context, Intent intent) {
        AlertDialog.Builder builder = new AlertDialog.Builder(context);

        builder.setIcon(android.R.drawable.ic_dialog_alert);
        builder.setTitle("登錄異常");
        builder.setMessage("You are forced to be offline. Please try to login again.");
        builder.setCancelable(false); //將對話框設爲不可取消
        builder.setPositiveButton("確定", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                ActivityCollector.finishAll(); //關閉所有的 Activity

                Intent intent = new Intent(context, LoginActivity.class);

                //由於我們是在廣播接收器裏啓動Activity，因此一定要給 Intent 加入 FLAG_ACTIVITY_NEW_TASK 這個標誌
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(intent); //重新啓動 登錄界面 LoginActivity
            }
        });

        AlertDialog alertDialog = builder.create();
        /*
        需要把對話框的類型設爲TYPE_SYSTEM_ALERT，不然它將無法在廣播接收器裏彈出
        */        // 需要設置AlertDialog的類型，保證在廣播接收器中可以正常彈出
        alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);

        alertDialog.show();
    }
}

BaseActivity 所有 Activity 的父類

package com.gao.broadcastreceivertest;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

/**
 * 創建 BaseActivity 類作爲所有 Activity 的父類
 */
public class BaseActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_base);

        ActivityCollector.addActivity(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        ActivityCollector.removeActivity(this);
    }
}

---

ActivityCollector 類用於管理所有的 Activity

package com.gao.broadcastreceivertest;

import android.app.Activity;

import java.util.ArrayList;
import java.util.List;

/**
 * 創建一個 ActivityCollector 類用於管理所有的 Activity
 */
public class ActivityCollector {
    public static List<Activity> sActivities = new ArrayList<>();

    public static void addActivity(Activity activity) {
        sActivities.add(activity);
    }

    public static void removeActivity(Activity activity) {
        sActivities.remove(activity);
    }

    public static void finishAll() {
        for (Activity activity : sActivities) {
            if (!activity.isFinishing()) {
                activity.finish();
            }
        }
    }

}